Strip edge conditioner

ABSTRACT

The self-centering edge conditioning unit for a moving sheet metal strip is an element placed in a strip conditioning line to assist in removing non-uniform terminal residual stresses which may be produced therein and which may actually result in physical deformation of the strip, such lateral curvature sometimes being known as &#39;&#39;&#39;&#39;chamber.&#39;&#39;&#39;&#39; The edge conditioning unit comprises a pair of assemblies pivotally mounted on two composite arms which have a common pivotal connection to a base frame. The arms are provided with lateral extensions, one of which is connected to a bracket for mounting an air cylinder and the other of which is connected to a piston rod projecting from the air cylinder. When energized, the air cylinder moves the arms in such fashion that the self-centering edge conditioning assemblies engage the opposite edges of a moving sheet metal strip. Each assembly comprises spaced bottom and top plates with the spacer at the center of each assembly serving as the pivot point for connecting that assembly to one of the pairs of arms. Each assembly also includes a pair of spaced-apart floating edge rolls having a central peripheral notch or recess in which the edge of the strip is engaged. Each edge engaging roll rotates against a pair of backup rolls which are pivotally mounted upon and between the top and bottom plates. The edge engaging rolls do not have a fixed center of rotation and are prevented from falling free of the assembly by a pair of pins which may be engaged by the periphery of the strip edge engaging roll when no strip is placed or passing between the assemblies.

United States Patent [1 1 (Main 1 STRIP EDGE CONDITIONER [75] Inventor: Emmerich I. Olah, Phoenix, Ariz. [73] Assignee: Interlake, Inc., Chicago, Ill.

[22] Filed: Sept. 17, 1971 [2]] Appl. No.: 181,302

Primary ExaminerRichard A. Schacher I Att0meyPrangley et al.

[57] ABSTRACT The self-centering edge conditioning unit for a moving sheet metal strip is an element placed in a strip conditioning line to assist in removing non-uniform terminal residual stresses which may be produced therein and Nov. 6, 1973 which may actually result in physical deformation of the strip, such lateral curvature sometimes being known as chamber. The edge conditioning unit comprises a pair of assemblies pivotally mounted on two composite arms which have a common pivotal connection to a base frame. The arms are provided with lateral extensions, one of which is connected to a bracket for mounting an air cylinder and the other of which is connected to a piston rod projecting from the air cylinder. When energized, the air cylinder moves the arms in such fashion that the self-centering edge conditioning assemblies engage the opposite edges of a moving sheet metal strip. Each assembly comprises spaced bottom and top plates with the spacer at the center of each assembly serving as the pivot point for connecting that assembly to one of the pairs of arms. Each assembly also includes a pair of spaced-apart floating edge rolls having a central peripheral notch or recess in which the edge of the strip is engaged. Each edge engaging roll rotates against a pair of backup rolls which are pivotally mounted upon and between the top and bottom plates. The edge engaging rolls do not have a fixed center of rotation and are prevented from falling free of the assembly by a pair of pins which may be engaged by the periphery of the strip edge engaging roll when no strip is placed or passing between the assemblies.

18 Claims, 7 Drawing Figures Nov. 6, 1973 PAIFNTEUHUV 6M5 3770.178

SHEET 10F 4 EN TOR EMMER/ I. OLAH 7 'TTYs.

PATENTEDNnv sum 3770.178

sum w 4 STRIP EDGE CONDITIONER The present invention relates to a self-centering edger unit for strip conditioning in the continuous production of steel strapping. The edger units heretofore in use were initially designed for use with heavy duty strip, as large as two inches wide and 0.060 inch thick. Because of the use for heavy duty stripping, it was necessary to provide a husky design which required accepting certain disadvantages. The prior art devices had unreliable centerline conduct of the strip, improper self-adjusting properties, and inadequate distribution of forces on the working tools. The prior art edgers needed counterbalancing weights or springs which were proven to be inadequate to the reliable control of center-guiding. Where it was required to give up counterbalancing, the result was unavoidable eccentric loading. The quality of performance of the prior art tool was deficient particularly on lighter weight strip material where the column strength of the strip is inadequate to stabilize the edger in the proper position for the required quality of the finished product.

A principal object of the present invention is to provide a new and improved self-centering strip conditioning edger unit which overcomes the disadvantages of the prior art devices.

Another object is to provide a new and improved strip edger unit wherein the balkiness of the prior art devices was minimized by avoiding heavier than necessary moving parts while retaining strength for the possible larger dynamic load at increased production speed.

Another object is to provide a new and improved strip edger unit which distributes evenly the work load through the edger rolls provided in the assemblies for such rolls.

Another object is to provide a new and improved strip-edger unit which avoids overload on the edger when irregularities of slit strip edges pass.

Another object is to provide a new and improved strip edger unit which holds a perfect centering of the work rolls to insure that the strip will always be properly centered.

Another object is to provide a new and improved strip edger unit which is appreciably more compact than the prior art and takes up about two-thirds of the space required by the commercially available devices.

Another object is to provide a new and improved strip edger unit wherein the parts are simple, easily manufactured, and of easy access for maintenance.

Other objects and advantages will become apparent from the following description taken in conjunction with the accompanying drawings and appended claims.

FIG. 1 is a side elevational view of the steel strip conditioning mechanism incorporating the self-centering edging unit of the present invention;

FIG. 2 is a front elevational view on an enlarged scale of the strip edge conditioning unit forming a part of the mechanism seen in FIG. 1;

FIG. 3 is a side elevational view of the strip edge conditioning unit taken from the right side of FIG. 2;

FIG. 4 is a plan sectional view taken along the line 4-4 of FIG. 2, looking in the direction of the arrows;

FIG. 5 is a detailed sectional view of the power unit mounting taken along the line 55 of FIG. 2, looking in the direction of the arrows;

FIG. 6 is a detail view, partly broken into section, of an edge'conditioning roll and its backup rolls; and

FIG. 7 is a side elevational view, partly broken into section, of the edging roll, backup rolls, and the mounting for the assembly thereof taken from the right side of FIG. 6.

Referring to FIG. 1, a strip conditioning assembly 10 is mounted on a frame 12 which includes an upright 14. Strip S is drawn through the strip conditioning assembly 10 by a power means, not shown, and enters the assembly 10 over guide rolls l6 journaled on bearing 18 mounted on the frame 12. The strip S is drawn through an edging unit 20, which is mounted on the frame upright 14, and a flattening unit 22 similarly mounted on the frame upright 14, and is then drawn over another direction controlling guide roll 24.

Referring to FIGS. 2 and 3, each edging unit 20 is mounted on a frame 26 having a base plate 28 which is secured to the upright 14 by bolts 30 and 32. The unit frame 26 includes an upper support bracket 34 having a horizontal shelf 36 and strengthening ribs 38. The bracket 34 is held in place by the mounting bolts 30. The shelf 36 has a slot 40 therein between the ribs 38 for the passage of the strip S therethrough.

Extending from the shelf 36 are three bearing plates 42 which together with back plate 43 of the bracket support a pair of pivot pins 44 held in place by set screws 46 threaded through appropriate openings in the center two of the bracket plates 42. The pivot pins are not continuous from front to rear of the unit but are interrupted between the center plates 42 to' permit the passage of strip S through the edger unit 20. Pivotably mounted on the pivot pins 40 are a large operating arm 48 and a small operating arm 50. The operating arms 48 and 50 each carry and swing identical strip edging assemblies 52 toward and from the centerline of strip movement.

Referring to FIGS. 6 and 7, each assembly 52 includes a top plate 54 and a bottom plate 56 which are separate and interconnected by spacers 58 and a centrally located pivot sleeve 60. The pivot sleeve 60 has shoulders 62 against which the inner faces of the plates 54 and 56 are held by the ends of the pivot sleeve which are spun into recesses 64in the outer faces of the plates. The ends of the spacers 58 are similarly spun into recesses 66 in the outer faces of the plates 54 and 56. The plates there provide a substantial support for the edging unit to be described hereinafter.

The large operating arm 48 as seen best in FIGS. 2 3, and 4 includes a pair of spaced-apart plates 68 which are secured together adjacent their lower ends by a bearing sleeve 70 welded to the inner faces of the plates. The plates 68 are welded to a pair of angleshaped plates 72 which have bearing holes 74 to receive the pivot pins 44. The plates 72 are spaced apart and secured together by cross braces 76 and 78 Welded to the upper and outer ends of the plates 72 is a U-shaped power unit supporting bracket 80 which as seen in FIG. 2 extends leftwardly of the centerline of travel of the strip S.

At their lower ends, the plates 68 of the arm 48 strad dle the assembly 52, and adjacent the bearingsleeve 70 the plate 68 has a bearing hole 82 through which extends a pivot pin 84 which projects through the sleeve 60 and is held in place by a keeper 86 which bears in a conventional manner against a shoulder of the pivot pin. Thus, as the arm 48 is pivoted about the pin 44, the

right edging assembly 52 (FIG. 2) will be swung toward and away from the centerline of movement of the strip S.

The small operating arm 50 comprises a pair of angularly shaped plates 88, the upper ends of which have bearing openings 90 to receive the pivot pins 44. At their lower ends the plates are separated and secured together by a bearing sleeve 92 which is similar to and has the same function as the bearing sleeve 70 for the arm 48. Adjacent their upper ends the plates 88 are secured together and spaced by a stop sleeve 94 which is welded to the inner faces of the plates 88. As seen in H6. 2, the underside of the plate portions 72 of the large arm 48 engages the stop sleeve 94 when the arms 48 and 50 are in their extreme outward or rest positions.

The unit thus described provides that the spacedapart plates 88 straddle the second of the assemblies 52, and they are provided with bearing holes 96 through which a shouldered pivot pin 98 extends. It projects through the plates 88 and is joumaled in the spacing sleeve 60 in the edger assembly 52 to be retained by a keeper 100.

The lower ends of the plates 88 are formed with leftward extensions 102 (FIG. 2). The arrangement just described swings the second of the assemblies 52 on the operating arm 50 toward and away from the centerline of movement of the strip 8. It should be noted from FIG. 2 that the operating arms 48 and 50 having a common pivot center on the pins 44 have a scissors-like action toward and away from the strip S. However, the edging assemblies 52 are each capable of engaging the strip S at separate and spaced points on each edge thereof, as described hereinafter, because the assem blies are swingably mounted upon the operating arms 48 and 50.

The arms 48 and 50 are controlled from a power unit 104 comprising an air cylinder 106 which has a piston 107 reciprocal thereon and is biased upwardly in the cylinder by a spring 109. It is moved downwardly by air under pressure entering through an air hose 108. Suitable conventional controls are provided for regulating the supply of air to the cylinder 106. Projecting downwardly from the cylinder 106 is a piston rod 110 which is connected to the piston 107 and is slidable through a bushing 1 12 mounted in a base plate 114 ofa cylinder mounting bracket 116. The cylinder mounting bracket 116 is fixed to the cylinder 106 by a pair of bolts 118 extending through the base plate 114 and into bottom cylinder head 120 of the cylinder. The bracket 116 includes a pair of upstanding arms 122 which are welded to the base plate 114 and have tapped openings in their upper ends through which pivot providing bolts 123 are threaded to mount the cylinder supporting bracket 1 16 to the U-shaped bracket 80 of the operating arm 48.

Thus, the cylinder 106 moves up and down with the movement of the bracket part 80 of the large operating arm 48.

The piston rod 110 descends from the cylinder 106 and is screwed into a tapped hole 124 in a mounting block 126 pivotally mounted on a pin 128 extending through holes in the outer ends of the extensions 102 of the plates 88, the pins 128 being held in place by C- clips 130. The anchored and proper positioning of the piston rod 110 in the mounting block 126 is insured by a jam nut 132 tightened against the upper face of the mounting block 126. The internal spring 109 in the cylinder 106 forces the piston and piston rod 110 up and the cylinder 106 downwardly, relatively, thus placing the upward extension portions of the large and small operating arms closer together and moving the edger assemblies 52 apart. This movement is limited by the engagement of the stop sleeve 94 on the small operating arm 50 against the underside of the plates 72 of the large operating arm 48. This is the full line or rest position as seen in FIG. 2. For operation of the selfcentering edging unit air under pressure is introduced into air cylinder 106 to cause the large operating arm 58 to pivot in a clockwise direction and the small operating arm 50 to pivot in the counter-clockwise direction bringing the edging assemblies 52 toward the centerline of strip movement.

The arms 48 and 50 of the assemblies 52 are further guided by a pair of arm connecting links 134 which are pivotally mounted on pins 136 extending between the plates 88 of the small operating arm 50 and the plates 68 of the large operating arm 48. The pins 136 extend through the bearing sleeves 92 and 70, respectively, being retained in position by C-clips 138 at their outer ends. The links 134 converge at their lower ends and pivot on a sleeve 140 (FIG. 3), through which extends a cam follower bolt 142 which has a roller head 144 slidably guided in a vertical slot 146 in and adjacent the bottom of the plate 28. The connecting links 134 aid in maintaining parallelism between the movement of the arms 48 and 50 and the positions of the edger assemblies 52 which are on opposite sides of the centerline of strip movement.

Each of the assemblies 52 has its operating mechanism mounted on and between the top and bottom plates 54 and 56 as best seen in FIGS. 6 and 7. The strip edge conditioning element comprises a pair of rolls 148, each having a V-shaped peripheral notch 150-at the longitudinal center thereof. The rolls 148 pivot beyond the inner edges of the plates 54 and 56 and the edges of the strip S engage and ride in the notches 150. As seen best in FIGS. 6 and 7, the rolls 148 float freely in position and do not rotate on a fixed pivot. Each roll 148, when engaged with the edge of the strip S, rides against a pair of backup rolls 152. Each backup roll is formed with a pair of rims 154 which have between them a double surface tread 156 against which the strip edge engaging roll 1418 rotates under the impetus supplied by the moving strip S. The strip S moves downwardly to rotate the edge roll 148 in the clockwise direction which in turn rides against the treads 156 of the backup rolls 152 to drive them in the counterclockwise direction.

The back-up rolls are mounted for rotation on pivot pins 158, each of which has a flange 160 which is seated in a recess in the outer face of the top plate 54. The pivot pins 158 are restrained against longitudinal movement by a keeper 162 which overlies the flanges of two adjacent pivot pins 158 and is bolted to the outer face of the top plate 54. The pivot pins 158 are fitted with conventional lubricating nipples 164 by means of which the bearings may be adequately lubricated for the free rotation of the backup rolls 152. The inner races of the backup rolls are properly centered on the pivot pins 158 in the assembly 52 by spacers 166.

Each of the strip edge conditioning rolls 148 is restrained against falling free of the assembly by a pair of pins 168 and 170 mounted in and projecting from a block 172 which is bolted in a recess 174 in the inner edge of the bottom plate 56. The pin 168 is fixed in the block 172, and the pin 170 has a head 176 thereon which is held against a shoulder 178 in a bore 180 in the block by a biasing spring 182 which is retained by a conventional threaded plug. The pin 170 can be moved out of retaining position by pushing it inwardly of the bore 180 to free the edge engaging roll 148 from restraint, and the freed roll may therefore be removed and replaced should that become necessary. When normally operating with the edge of the strip S in the notch in the roll 148, thelatter will not contact or touch either of the pins 168 and 170. These pins become functional in the retaining function only when the edger unit 20 is at rest or no strap is present between the assemblies 52. The pins then prevent the roll 148 from falling free of the assembly 52.

In rest condition, the biasing spring 109 within the air cylinder 106 acts to hold the scissor-mounted operating arms 48 and 50 in their withdrawn position and the stop sleeve 94 against the. leftward extension of the arm 48. With the edging unit in this condition, a strip of appropriate width may be threaded through the assembly. Air under pressure is admitted to the cylinder 106 by opening the appropriate control valve. The air will act on the power unit 104 to drive the piston rod 110 downwardly to rotate the arm 50 in the counterclockwise position about the pivot 44. The same air pressure will move the cylinder 106 upwardly to raise the mounting bracket 116 and rotate the arm 48 in the clockwise direction about the pivot pins 44. The simultaneous inward movement of the arms 48 and 50 swings the strip edge engaging assemblies 52 toward the centerline of movement of the strip S. This swinging is terminated when the notches 150 in the four rolls 148 engage the edges of the strip S. The amount of movement of the assemblies 52 is determined, therefore, by the width of the strip being conditioned.

As the strip S is drawn through that conditioning assembly 10, the rolls 148 function to condition the strip, and in conjunction with the flattening units 22 to remove the chamber therefrom for the reasons discussed in the Wognum et al. US. Pat. No. 3,006,401.

From the foregoing description of the construction and operation of the strip edge conditioning unit of the present invention, it is clear that the advantages and objectives that were set forth for this unit at the outset of this specification are attained. What is claimed as new and desired to be secured by United States Letters Patent is:

What is claimed is:

1. An edge conditioning mechanism for a moving sheet metal strip comprising in combination a frame, a pair of self-centering strip edge engaging assemblies, means pivotally mounting said assemblies on said frame on a common pivot for swinging movement toward and away from the centerline of strip movement, a power unit connected to said mounting means to move said assemblies toward the centerline of strip movement, and means in said assemblies to engage the opposite edges of a moving strip for the conditioning thereof.

2. The combination set forth in claim 1, including means biasing said assemblies away from the centerline of strip movement, and means limiting the extent of movement by said biasing means.

3. The combination set forth in claim 2, wherein said movement extent limiting means comprises a stop member carried by one of said arms and engageable with the other of said arms when said assemblies are in their fully withdrawn position.

4. The combination set forth in claim 1, wherein each of said assemblies comprises top and bottom plates secured together, a pair of floating strip edge engaging rolls, and a pair of backup rolls for each of said strip edge engaging rolls having recessed tread defining peripheries on which said strip edge engaging roll rotates when the latter engages the moving strip edge, said backup rolls being pivoted to and between said top and bottom plates.

5. The combination set forth in claim 4, wherein each strip edge engaging roll has a peripheral notch in the cylindrical surface at the longitudinal center thereof.

6. The combination set forth in claim 4, including retaining means to prevent each strip edge engaging roll from falling from the assembly when no strip is present or passing between said assemblies.

7. The combination set forth in claim 6, wherein said retaining means comprises a pair of retaining pins, a block mounting said pins, one of said pins being fixed in said block and the other being slidable therein between retaining and retracted positions, and means biasing said other pin to retaining position from which it may be retracted by depressing said biasing means to retract said pins so that said strip engaging roll may be removed or inserted.

8. An edge conditioning mechanism for a moving sheet metal strip comprising in combination a frame, a pair of self-centering strip edge engaging assemblies, first and second operating arms pivotally mounted on said frame, means pivotally mounting one of said edge engaging assemblies to each operating arm for swinging each assembly toward and away from the centerline of the strip movement, a power unit interposed between said operating arms to swing said assemblies toward the centerline of strip movement, and each of said strip edge engaging assemblies including spaced top and bottom plates secured together, a pair of strip edge engaging rolls, a notch in the cylindrical surface of each roll in which the strip edge is engaged, a pair of backup rolls for each of said strip edge engaging rolls having recessed peripheries in which said strip edge engaging roll rotates when the latter engages the moving strip edge, said backup rolls being pivoted to and between said top and bottom plates, and a pair of strip edge roll retaining pins for each strip edge retaining roll to prevent the latter from falling from the assembly when no strip is present or passing between said assemblies.

9. A strip edge conditioning assembly for use in a strip edge conditioning unit, comprising in combination spaced top and bottom plates, a strip edge engagingroll positioned to float between said plates and to project slightly from therebetween, and a pair of pivotally mounted backup rolls against which said strip edge engaging roll rotates when said strip edge engaging roll is contacted against a moving strip.

10. The combination set forth in claim 5, wherein said strip edge engaging roll has a peripheral notch at its longitudinal center in which the strip is engageable.

11. The combination set forth in claim 10, including retaining means to prevent said strip edge engaging roll from falling free of the assembly.

12. The combination set forth in claim 11, wherein said. retaining means comprises a pair of retaining pins, a block mounting said pins on said bottom plate, one of said pins being fixed in said block and the other being slidable therein between retaining and retracted positions, and means biasing said other pin to retaining position, said other pin being movable to retracted position by depressing said bearing means so that said strip edge engaging roll may be removed or inserted.

13. A strip edge conditioning assembly for use in a strip edge conditioning unit comprising in combination top and bottom plates, means securing said plates together in spaced relationship, a pair of strip edge engaging rolls positioned to float between said plates and to project slightly from therebetween, each strip edge engaging roll having a peripheral notch at its longitudinal midpoint in which the strip is engageable, a pair of backup rolls against which each strip edge engaging roll rotates when said strip edge engaging roll is contacted against a moving strip, pivot pins mounting said backup rolls to and between said plates, pairs of retaining pins mounted on said bottom plate and projecting inwardly of said plates to prevent said strip edge engaging rolls from falling free of the assembly, and means biasing one of said retaining pins in each pair to retaining position from which it may be moved by depressing said biasing means to move said one retaining pin out of retaining position so that said strip edge engaging roll may be removed or inserted.

14. An edge conditioning mechanism for a moving metal strip comprising in combination a frame, a pair of self-centering strip edge engaging assemblies, a pair of arms pivotally mounted to said frame on a common pivot for swingably mounting said assemblies for movement toward and away from the center-line of strip movement, means connected to said arms for biasing said assemblies away from the centerline of strip movement, means limiting the extent of movement by said biasing means, a power unit connected to said arms to move said assemblies toward the centerline of strip movement, and means in said assemblies to engage the opposite edges of a moving strip for the conditioning thereof.

15. The'combination set forth in claim 14, wherein said power unit comprises an air cylinder connected to one of said arm extensions, a piston reciprocable therein, a piston rod connected to said piston, projecting from said cylinder and connected to the other of said arm extensions, and said biasing means comprises a spring acting on said piston.

16. An edge conditioning mechanism for a moving sheet metal strip comprising in combination a frame, a pair of self-centering strip edge engaging assemblies, means swingably mounting said assemblies on said frame for movement toward and away from the centerline of strip movement, a power unit connected to said mounting means to move said assemblies toward the centerline of strip movement, and means in said assemblies including at least two floating edge engaging rolls in each assembly to engage the opposite edges of a moving strip for the conditioning thereof.

17. The combination set forth in claim 16, including a pair of backup rolls mounted on fixed pivots against which each of said edge engaging rolls rotates, said backup rolls having recessed peripheries to define treads for said edge engaging rolls.

18. The combination set forth in claim 16, including means to retain said strip engaging rolls in said assemblies so as to engage the strip edges when said power unit is engaged to move said assemblies toward the centerline of strip movement. 

1. An edge conditioning mechanism for a moving sheet metal strip comprising in combination a frame, a pair of self-centering strip edge engaging assemblies, means pivotally mounting said assemblies on said frame on a common pivot for swinging movement toward and away from the centerline of strip movement, a power unit connected to said mounting means to move said assemblies toward the centerline of strip movement, and means in said assemblies to engage the opposite edges of a moving strip for the conditioning thereof.
 2. The combination set forth in claim 1, including means biasing said assemblies away from the centerline of strip movement, and means limiting the extent of movement by said biasing means.
 3. The combination set forth in claim 2, wherein said movement extent limiting means comprises a stop member carried by one of said arms and engageable with the other of said arms when said assemblies are in their fully withdrawn position.
 4. The combination set forth in claim 1, wherein each of said assemblies comprises top and bottom plates secured together, a pair of floating strip edge engaging rolls, and a pair of backup rolls for each of said strip edge engaging rolls having recessed tread defining peripheries on which said strip edge engaging roll rotates when the latter engages the moving strip edge, said backup rolls being pivoted to and between said top and bottom plates.
 5. The combination set forth in claim 4, wherein each strip edge engaging roll has a peripheral notch in the cylindrical surface at the longitudinal center thereof.
 6. The combination set forth in claim 4, including retaining means to prevent each strip edge engaging roll from falling from the assembly when no strip is present or passing between said assemblies.
 7. The combination set forth in claim 6, wherein said retaining means comprises a pair of retaining pins, a block mounting said pins, one of said pins being fixed in said block and the other being slidable therein between retaining and retracted positions, and means biasing said other pin to retaining position from which it may be retracted by depressing said biasing means to retract said pins so that said strip engaging roll may be removed or inserted.
 8. An edge conditioning mechanism for a moving sheet metal strip comprising in combination a frame, a pair of self-centering strip edge engaging assemblies, first and second operating arms pivotally mounted on said frame, means pivotally mounting one of said edge engaging assemblies to each operating arm for swinging each assembly toward and away from the centerline of the strip movement, a power unit interposed between said operating arms to swing said assemblies toward the centerline of strip movement, and each of said strip edge engaging assemblies including spaced top and bottom plates secured together, a pair of strip edge engaging rolls, a notch in the cylindrical surface of each roll in which the strip edge is engaged, a pair of backup rolls for each of said strip edge engaging rolls having recessed peripheries in which said strip edge engaging roll rotates when the latter engages the moving strip edge, said backup rolls being pivoted to and between said top and bottom plates, and a pair of strip edge roll retaining pins for each strip edge retaining roll to prevent the latter from falling from the assembly when no strip is present or passing between said assemblies.
 9. A strip edge conditioning assembly for use in a strip edge conditioning unit, comprising in combination spaced top and bottom plates, a strip edge engaging roll positioned to float between said plates and to project slightly from therebetween, and a pair of pivotally mounted backup rolls against which said strip edge engaging roll rotates when said strip edge engaging roll is contacted against a moving strip.
 10. The combination set forth in claim 9, wherein said strip edge engaging roll has a peripheral notch at its longitudinal center in which the strip is engageable.
 11. The combination set forth in claim 10, including retaining means to prevent said strip edge engaging roll from falling free of the assembly.
 12. The combination set forth in claim 11, wherein said retaining means comprises a pair of retaining pins, a block mounting said pins on said bottom plate, one of said pins being fixed in said block and the other being slidable therein between retaining and retracted positions, and means biasing said other pin to retaining position, said other pin being movable to retracted position by depressing said bearing means so that said strip edge engaging roll may be removed or inserted.
 13. A strip edge conditioning assembly for use in a strip edge conditioning unit comprising in combination top and bottom plates, means securing said plates together in spaced relationship, a pair of strip edge engaging rolls positioned to float between said plates and to project slightly from therebetween, each strip edge engaging roll having a peripheral notch at its longitudinal midpoint in which the strip is engageable, a pair of backup rolls against which each strip edge engaging roll rotates when said strip edge engaging roll is contacted against a moving strip, pivot pins mounting said backup rolls to and between said plates, pairs of retaining pins mounted on said bottom plate and projecting inwardly of said plates to prevent said strip edge engaging rolls from falling free of the assembly, and means biasing one of said retaining pins in each pair to retaining position from which it may be moved by depressing said biasing means to move said one retaining pin out of retaining position so that said strip edge enGaging roll may be removed or inserted.
 14. An edge conditioning mechanism for a moving metal strip comprising in combination a frame, a pair of self-centering strip edge engaging assemblies, a pair of arms pivotally mounted to said frame on a common pivot for swingably mounting said assemblies for movement toward and away from the center-line of strip movement, means connected to said arms for biasing said assemblies away from the centerline of strip movement, means limiting the extent of movement by said biasing means, a power unit connected to said arms to move said assemblies toward the centerline of strip movement, and means in said assemblies to engage the opposite edges of a moving strip for the conditioning thereof.
 15. The combination set forth in claim 14, wherein said power unit comprises an air cylinder connected to one of said arm extensions, a piston reciprocable therein, a piston rod connected to said piston, projecting from said cylinder and connected to the other of said arm extensions, and said biasing means comprises a spring acting on said piston.
 16. An edge conditioning mechanism for a moving sheet metal strip comprising in combination a frame, a pair of self-centering strip edge engaging assemblies, means swingably mounting said assemblies on said frame for movement toward and away from the centerline of strip movement, a power unit connected to said mounting means to move said assemblies toward the centerline of strip movement, and means in said assemblies including at least two floating edge engaging rolls in each assembly to engage the opposite edges of a moving strip for the conditioning thereof.
 17. The combination set forth in claim 16, including a pair of backup rolls mounted on fixed pivots against which each of said edge engaging rolls rotates, said backup rolls having recessed peripheries to define treads for said edge engaging rolls.
 18. The combination set forth in claim 16, including means to retain said strip engaging rolls in said assemblies so as to engage the strip edges when said power unit is engaged to move said assemblies toward the centerline of strip movement. 